Dewatering is not that important in these older engines. I and the people I know with 7.3idi do not dewater there oil at all beyond heating and letting water and food particles to settle out for several days. Then I filter. These older engines are much more tolerant and do not react at all to the water suspended in the oil. It can cause corrosion leaving water in the injection pump and injectors but that is why you start on diesel and end on diesel. BEWARE of the water that settles out and is on the bottom of your barrels.

Setting it up and filtering is a messy and time consuming thing. I consider this to be the biggest drawback. I go through 30-50 gal a week and sometimes get tired of spending my Sunday's filtering oil.

Bio has to be filtered and processed with no modifications to the truck.

Straight wvo only has to be filtered once the truck is set up but you have to remember to start and stop on diesel.